Bug ID 833685: Idle async handlers can remain loaded for a long time doing nothing

Last Modified: Sep 13, 2023

Affected Product(s):
BIG-IP ASM(all modules)

Known Affected Versions:
12.1.0, 12.1.1, 12.1.2, 12.1.3,,,,,,,, 12.1.4,, 12.1.5,,, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3, 13.0.1, 13.1.0,,,,,,,,, 13.1.1,,,,, 13.1.3,,,,, 14.0.0,,,,,, 14.0.1,, 14.1.0,,,,,, 14.1.2,,,,,,, 15.0.0, 15.0.1,,,,, 15.1.0,,,,

Fixed In:

Opened: Oct 04, 2019

Severity: 3-Major


Idle async handlers can remain loaded for a long time doing nothing because they do not have an idle timer. The sum of such idle async handlers can add unnecessary memory pressure.


Depletion of memory by lingering idle async handlers may deprive other processes of sufficient memory, triggering out-of-memory conditions and process failures.


This issue might result from several sets of conditions. Here is one: Exporting a large XML ASM policy and then leaving the BIG-IP system idle. The relevant asm_config_server handler process increases its memory consumption and remains that way, holding on to the memory until it is released with a restart.


-- Restart asm_config_server, to free up all the memory that is currently taken by all asm_config_server processes and to impose the new MaxMemorySize threshold: --------------- # pkill -f asm_config_server --------------- -- Restart asm_config_server periodically using cron, as idle handlers are soon created again.

Fix Information

Idle async handlers now exit after 5 minutes of not receiving any new calls.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips